Shrimp culture plays an important role in aquaculture of China. In recent years, problems such as degenerating germplasm, decreasing seedling quality and severe diseases, have embarrassed healthy development of the shrimp culture. So it is necessary to improve shrimp germplasm by biological techniques with accelerated growth or enhanced stress resistance in marine aquaculture. Genetic improvement has been implied well in several aquaculture animals such as fish and shellfish at cellular and chromosome levels by using biological techniques. It can increase aquaculture yields and improve quality by using sterility of triploids on one hand. These triploids can also be taken as carriers for transgenic techniques of aquatic organisms. Utilization of triploids can solve the safety problem associated with transgenic animals to avoid wild germplasm contamination coming from escape of transgenic animals. So the triploid induction technique is expected to solve or relieve the increasing problems in shrimp culture. In November 2003, scientists emphasized that combining transgenic technique and triploid is one of the most efficient methods to relieve environment hazards brought by transgenic animals at the consultative meeting about transgenic animals' security held in Rome by Food and Agriculture Organization of the United Nations.
Due to the special characteristics of reproduction of shrimp, successful cases of triploid shrimp induction in batches was reported only in Chinese shrimp recently (see Li, F. H., Xiang, J. H., Zhou, L. H., Wu, C. G., Zhang, X. J., 2003. Optimization of triploid induction by heat shock in Chinese shrimp Fenneropenaeus chinensis. Aquaculture 219: 221-231), which has accomplished in the inventors' laboratory. However, there is no report on successful induction in tropical shrimp such as Penaeus merguiensis and Metapenaeus ensis. 